How to Use Labview to Control Dual Channel Signal Generators to Synchronize Their Outputs

[penguin_love]

Dual-channel signal generator,
Using the first channel as a reference, the second channel performs phase scanning from 0 to 30 degrees at the same frequency. The problem encountered is that the two channels cannot be homogenously output. During phase scanning in the second channel, the phase difference of the two channels measured by the oscilloscope is not output according to the phase difference set by the program, and the phase difference is a random beat.
How to use Labview to synchronize the signals of two channels to achieve phase scanning

[GerdW]

Hi penguin,

I guess the answer is found in the manual of your "dual channel signal generator", but you didn't attach such a manual nor did you name that signal generator…

Did you read the manual?

[penguin_love]

The model of the dual channel signal generator is the 33512B, which is easily synchronized directly on the instrument. But how to use Labview to achieve dual-channel synchronization does not know, tried many cases did not succeed. I downloaded the instrument driver on the official website of NI. I called the Agilent 3352X Series. The VI inside is indeed able to control the signal generator. However, we have not yet achieved the function we need, ie, the phase of the second channel signal is scanned. Its phase value is relative to the first channel

[GerdW]

Hi penguin,

which is easily synchronized directly on the instrument.

Then there are surely SCPI commands to achieve the same remotely.

I don't think I will read the Chinese version of the manual…

[cstorey]

You probably want to look at this thread - https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/agilent-33512B-dual-channel-phase-alignment/...

[penguin_love]

Dear cstorey,

After using  Sync Internal Phase.vi, synchronization can indeed be achieved, but each time the phase changes, the waveform will have jitter and the change will not be smooth. I want to consult you how to solve this problem, thanks!

[cstorey]

Hmm.

You have Enable Output in the inner while loop, but you don't need to do that every time (since you never turn it off!).  Take that outside the loop and see if that reduces jitter.  You might also call Keysight and see what they recommend.  How much time does each while loop iteration take?  I think perhaps you need some delay, the instrument is trying to process a lot of changes to the output waveform all at once.  I would add a 1s delay between successive phase increments.

If none of that helps then I suggest you call a Keysight App Engineer and see what the limitations are on the Sync Phase feature and if noise/jitter are expected.  They have much more experience with it that I do. 🙂

Craig

[oscarfonseca]

penguin_love,

Do you have an example/image of how this jitter looks like? Perhaps it's easier for the folks here to understand what you are asking or trying to solve if they can see it.

All the best,

[cstorey]

Another idea, though I haven't tried this and don't have a 3352x to test it on.

Disable output, change all the parameters then sync phase, then enable output.  If that can be done you shouldn't see jitter.

But yes, some pictures of the signals would help.